Circuit-interrupting device.



E. R. CARICHOFF.

CIRCUIT INTERRUPTING DEVICE.

APPLICATION FILED DEC-26.1912.

Patented Dec. 14, 1915.

Fig.2.

Fig.4.

Fig. 3.

Inventor Eufiene RCarichoff, by

His Atornev.

Witnesses:

U N l IED STATESPATENT OFFICE.

EUGENE CARICI-IOFF, SCHENECTADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

cxncurr-mrnnnurmme nnvronl T 0 all whom it may concern:

Be it known that I, EUGENE R. CARIGHOFF, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certainnew and useful Improvements in Circuit-Interrupting, Devices, of which the following is a are extinguishing devices of the character in c which a magnetic circuit is caused to, act upon the arc to disrupt it, such devices being commonly known as magnetic blowouts. It is well known that when an arc 1s formed along a line parallel to a conductor in which current is flowing, the direction of current flow in the arc and in the conductor being the same the arc will be attracted toward the conductor. This is so by reason of the attractive force existing between the lines of force in the space between the conductor and the arc since in this space the lines of force in two magnetic fields will be parallel and in opposite directions. This efi'ect is augmented by the repulsion elfect existing between the lines of force beyond the arc in a direction away from the conductor. Likewise if the current in the conductor is in the opposite direction from that in the arc the latter will be repelled.

In utilizing the magnetic field for blowing out an are it is common to cover the pole pieces between which the arc is formed with insulating material so as to prevent the are from coming in contact with the pole-pieces. Frequently no attempt is made to keep the are out of contact with the insulation and in some cases the arc is intentionally blown against the insulating covering of the polepieces. Even if the arc is not intentionally blown against the pole-pieces the magnetic attraction between the iron pole-pieces and the arc will cause the arc to impinge against the covering of the pole-pieces. It has also been proposed to have the are blown against the magnetizing coil'so that the arc will be broken by encircling the coil. I have found that the most efficient and lasting arrangement is to have the are blown away from the Specification of Letters Patent.

blown out.

Patented Dec. 14, 1915.

Application filed December 26, 1912. Serial No. 738,527.

"coil in-such a manner that it will be kept out of contact with the pole-pieces or the sides of the arc chute. In, carrying out my invention I so arrange the parts that the magnetic flux in the pole-pieces repels the arc and causes it to maintain a position intermediate the pole-pieces while it is being The arrangement is also such that the are is blown in a direction away from the magnetizing coil.

In the accompanying drawing illustrating one embodiment of my invention, Figure 1 is a diagrammatic view illustrating the ordinary form of magnetic blow-out'of the prior art; Fi 2 is a diagrammatic view of a mag netic b ow out construction in accordance with my invention, and Figs. 3 and 4 show an electromagnetic switch provided with my improved magnetic blowout.

Referring first to Fig. 1, 10 represents the magnetizing coil of a blow-out of ordinary form having a core 11 and pole-pieces 12 and 13 extending laterally from the core 11. For purposes of illustration these pole pieces 12 and 13 are shown as being parallel with each other and at right angles to the core 11. The circuit breaking contacts are located be tween the pole-pieces 12 and 13 and the are formed between these contacts is represented by the conductor 14. Assuming that current is passing through the coil 10 from the terminal 15, the direction of flux throu h the core and pole-pieces will be as shown y the. arrows extending along the pole-pieces. Assuming that the current through the contacts and hence through the are 14 is in a direction at right angles to the plane of the paper and flowing from the back tothe front of the paper, the direction of the lines of force surrounding the arc will be as shown by the arrows. It will be seen that the lines of force in the pole-piece 12 are parallel with and in the dpposite direction from the lines of force surrounding the arc and between the arc and the pole-piece so that the arc will be attracted ,toward the pole-piece 12.- It is also seen that the lines offorce in the pole-piece 13 are parallel with and in the opposite direction from the lines of force surrounding the are 14 and between the arc and the pole-piece. The are will therefore be attracted toward the polepiece 13. In other words, the arc is drawn toward both pole-pieces. Looking now at the lines of force in the space betweenthe two pole-pieces it will be noted that the direction is from the pole-piece 12 to the pole piece 13. The lines of force, therefore, surrounding the arc and between the arc and the coil 10 will be in the same direction. and will therefore cause the arc to be repelled from the coil. This repulsion is augmented by the attraction between the lines of force surrounding the arc and the lines of force in the space between the pole-pieces but on the side of the are away from the coil. With this arrangement, therefore, the arc, while it would be repelled from the coil, would be blown toward the pole-pieces. It will be observed that if the current through the contacts and the arc 14 should be reversed from the directionshown in the drawing the arc will be repelled away from the pole-piece but will be attracted toward the coil.

in Fig. 2 which illustrates my present invention the arc will be repelled from the pole-pieces and also repelled from the magnetizing coil. This I have accomplished by causing the lines of force in the portion of the pole-pieces adjacent the arc to be reversed with reference to the direction of the lines of force in the main body of the polepieces. By looking at this figure it will be seen that the directions of the flux in the pole-pieces 17 and 16 are the same as in the pole-pieces 12 and 13 respectively of Fig. 1 and the direction of the flux, therefore, between the pole-pieces is the same as before. The direction of the current through the arc is also the same as in Fig. 1. As shown in the drawings, the flux in the bent ends 18' and 19 of the pole-pieces is in the reverse direction from that in the main body of the pole-pieces. The direction of the flux, however, between the pole pieces is not changed. Following now the direction of the lines of force as indicated by the arrows it will be found that the flux in the end portions 18 and 19 of the pole-pieces is parallel with and in the same direction as the flux in the field surrounding the arc and the arc will therefore be repelled from both poles and thus be forced to assume a position intermediate the poles. It will be noticed, however, that the direction of the flux in the field between the pole-pieces is the same as the direction of the fiux surrounding the arc and between the arc and the winding so that the arc will be repelled from the winding This effect will be augmented by the attraction between the lines of force in thetwo fields on the side of the are away from the winding. The re sult of this arrangement is that the arc is not only repelled from the polepieces but is also blown away from the winding. It will be understood, of course, that T have illustrated in this figure one method of carrying out my invention and that it is not intended that my invention should be limited to the particular arrangement shown.

meager Tn Figs. 3 and 4 T have shown my invention applied to an electro-magnetic switch of standard design. Referring to these figures it will be seen that the actuating winding 20 operates the core 21 to lift the pivoted switch arm 22 provided with the contact 23 into engagement with the stationary contact 24. These contacts 23 and 24 are located in an arc chute composed of plates 25 of insulating material extending downwardly from the magnetizing winding 26 over the contacts. Secured to the ends of the core 27 of the magnetizing winding are the pole-pieces 28 and 29 which project downwardly along the outside of the insulating plates 25 .of the-arc chute. These pole-pieces extend laterally from the core 27 and then fold inward. The inner folds It will be noted that the pole-pieces are pro vided with slots 31 which tend to prevent the lines of force from going across the polepieces diagonally but this is not an essential feature of my invention which is in no sense limited to the particular arrangement of the pole-piece or other parts shown. The are which is formed between the contacts 23 and 24: will be intermediate the polepieces 28 and 29; that is, it will occur in a position substantially midway between the backward folds of these two polepieces. Whether or not the arc occurs at an exactly central position between the polepieces will make no difference so far as the operation of the device is concerned, nor will it make any difference if the arc is formed somewhat inward toward the coil from the ends of the folded back portions as shown in Fig. 3, since the tendency of the flux will always be to force the arc toward the central 'posi. tion between the polepieces and outward away from the coil. The general shape of the pole-pieces is the same as that shown in Fig. 2, and accomplishes the same result, namely, the forcing of the are which forms between the contacts 23 and 2a away from the coil 26 and at the same time preventing it from impinging upon the sides of the arc chute.

It should be understood that T do'not limit my invention to the particular arrangement 'sho-wn since various modifications of my inthe arc is formed and means whereby the magnetic fiux generated by a current in said winding in the portion of the pole-pieces adjacent the arc repels the arc away from the pole-pieces 2. The combination with are forming contacts, of a blow-out device therefor comprising a magnetizing winding in series with the contacts having pole-pieces between which the arc is formed and means whereby the magnetic flux generated by a current in said winding repels the are away from the winding along a path intermediate of the pole-pieces.

3. The combination with arc forming con tacts, of a blowout device therefor comprising a magnetizing winding in series with the contacts having pole-pieces between which the arc is formed and means whereby the magnetic flux in said pole-pieces generated by a current in said winding repels the arc away from the pole-pieces and the flux across the space in which the arc is formed causes the arc to move away from the wind- 4. I The combination with are forming contacts, of a blow-out device therefor comprising a magnetizing winding in series with the contacts having pole-pieces between which the arc is formed extending laterally from the axis of said winding and means whereby the magnetic flux in the portion of said pole-pieces adjacent the arc generated by a current in said winding repels the are away from the pole-pieces and the flux across the space in which the arc is formed causes the arc to move away from the winding.

5. The combination with are forming contacts, of a blow-out device therefor comprising a magnetizing winding in series with the contacts having pole-pieces between which the arc is formed extending laterally from the axis of said winding said pole-pieces being turned inward adjacent the contact to change the direction of the flux in the turned portion with reference to the direction of the flux in the unturned portion of the polepieces.

In witness whereof, I have hereunto set my hand this 24th day of December, 1912.

EUGENE R. CARICHOFF.

Witnesses:

BENJAMIN B. HULL, MARGARET E. VVooLLEY. 

